This mentored research training grant proposal is designed to achieve two major NIDA goals: 1) to train new clinical researchers, and 2) to promote research that advances understanding of prescription opioid use and misuse. The following proposal will equip the candidate with highly relevant training for a career exploring an area of great need: how psychological impairment and pain interact over time to create both persistent prescription opioid use and subsequent opioid misuse. We propose the following specific aims: Aim 1: To characterize the influence of psychological distress, pain, and self-perceived susceptibility to addiction on the persistence of opioid use and rates of misuse following surgery. Aim 2: To characterize the effect of preoperative gabapentin on the rate of opioid and pain cessation. We will address these specific aims by preoperatively characterizing fear, depression, anxiety, PTSD symptomatology and self-perceived addiction susceptibility using validated measures. Following surgery, we will longitudinally follow patients to measure opioid use and pain until patients report cessation of both prescription opioids and pain. Using time to opioid cessation, we will construct a novel survival curve that describes the natural history of opioid cessation following surgery. Using survival analysis, we will characterize factors influencing the rate of opioid cessation. Subsequent longitudinal follow-up will intermittently assess prescription opioid use and misuse. Completion of this aim will identify patients at greatest risk of persistent opioid use and misuse for participation in the feasibility study proposed in Aim 2. Pre-operatively administered gabapentin reduces early post-operative pain severity and pre-operative anxiety (both shown by our preliminary data to promote persistent opioid use), and may reduce the persistence of prescription opioid use and pain following surgery. In Aim 2 we will evaluate all aspects of our ability to conduct a full randomized controlled trial of gabapentin to reduce the persistence of prescription opioid use following surgery. PUBLIC HEALTH RELEVANCE: Successful completion of these aims will advance public health by 1) identifying factors leading to persistent opioid use and misuse for the millions of Americans undergoing surgery each year, and 2) establishing the post-surgical setting as a model for testing interventions that will reduce persistent opioid use as well as persistent pain.